Adder.jj文件定义

/* adder.jj Adding up numbers */
options {
STATIC = false ;
}
PARSER_BEGIN(Adder)
import java.io.*;
class Adder {
public static void main( String[] args )
throws ParseException, TokenMgrError {
Adder parser = new Adder( System.in ) ;
parser.Start( System.out ) ;
}

double previousValue = 0.0 ;
}
PARSER_END(Adder)

SKIP:{" "}
TOKEN:{< EOL : "\n"|"\r"|"\r\n" >}
TOKEN:{< PLUS : "+">}
TOKEN :{ < MINUS : "-" > }
TOKEN:{< TIMES : "*" > }
TOKEN:{< DIVIDE : "/" > }
TOKEN:{< OPEN_PAR : "(" > }
TOKEN:{< CLOSE_PAR : ")" > }
TOKEN:{< PREVIOUS : "$" > }

TOKEN:{< NUMBER : <DIGITS>| <DIGITS>"." <DIGITS> | <DIGITS>"."|"." <DIGITS> >}
TOKEN : {< #DIGITS : (["0"-"9"])+ >}

void Start(PrintStream printStream) throws NumberFormatException :
{}
{
(
previousValue = Expression()
<EOL>
{ printStream.println(previousValue); }
)*
<EOF>
}
double Expression() throws NumberFormatException :
{
double i;
double value;
}
{
value = Term()
(<PLUS>
i = Term()
{ value += i;}
|
<MINUS>
i = Term()
{ value -= i; }

)*
{ return value; }
}
double Primary() throws NumberFormatException :
{
Token t;
double d;
}
{
t = <NUMBER>
{ return Double.parseDouble( t.image ); }
|
<PREVIOUS>
{ return previousValue; }
|
<OPEN_PAR> d = Expression() <CLOSE_PAR>
{ return d; }
|
<MINUS> d = Primary()
{ return -d; }
}


double Term() throws NumberFormatException :
{
double i;
double value;
}
{
value = Primary()
(
<TIMES>
i = Primary ()
{ value *= i;}
|
<DIVIDE>
i = Primary ()
{ value /= i; }
)*
{ return value; }
}